As is known in the art, with the advancement of both structural and functional imaging technologies (i.e., modalities) such as computed tomography (CT), magnetic resonance (MR), fluoro, ultrasound, positron emission tomography (PET), singleton photon emission computed tomography, there have been a significant increase in the use of image fusion technologies, dealing with aligning images into a common reference space and visualizing the fused results, in a variety of medical clinical applications ranging from screening, diagnosis, intervention & surgery, to follow-up.
In intervention and surgery applications, image fusion has become a pivotal technology to bring relevant image information obtained from different imaging modality either pre-operative (pre-op) or intra-operative (intra-op) (i.e., occurring, carried out, or occurring during surgery or intervention) into the intervention and surgical workspace to improve the accuracy, efficiency, and safety of the navigation of the treatment device navigation and the delivery of treatment. Images for intervention and surgical applications come in more diverse forms than other type of clinical applications. Often high quality multimodal pre-op three-dimensional (3D) or 3D+t (where t is time) images are registered (i.e., fused or merged) with low quality but real-time 2D or 2D+t images, which pose a great amount of challenges to fusion algorithms. As a result, often special fusion algorithms are developed for each special interventional and surgery application as illustrated in FIG. 1. This dominant R&D paradigm in image fusion has been the main driving force for its success in interventional and surgical labs. However, as the number of interventional and surgical applications require image fusion further increase rapidly, the current practice become more a hindrance as often for each new image source to be fused, a specialized fusion algorithm has to be developed and validated, whereas similar problems could have been solved in another application context with slightly different ways of handling the data and registration.
Thus, while images acquired using different modalities are frequently registered and displayed as fused images, one-to-one and special registrations are done for specific procedures. That is, if a CT image had been obtained and then an ultrasound image was requested, the image space of the ultrasound image was fused into the image space of the previous CT. If then a PET image was required, the PET image space was fused into the CT image space, and so one in a one-to-one manner.